Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds substantive behavioral detail beyond the annotations: platform-specific return semantics, the Google Business resource-path format, and the WhatsApp metadata fields (display_phone_number, quality_rating, messaging_limit_tier, etc.). It does not describe pagination or general return shape, keeping it short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The core purpose is front-loaded in the first clause before the platform enumeration. The platform list is dense but each entry earns its place by defining a distinct meaning; the run-on single-paragraph form is slightly hard to scan but there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries return-value burden, and it does so for the tricky cases (Google Business resource paths, WhatsApp metadata) plus states which platforms are supported. It omits a general description of the response shape and pagination, so it is strong but not exhaustive for a list tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With a single parameter and 100% schema description coverage ('Profile hashid'), the schema already fully documents the input and the description adds no further meaning for profile_id. The description's extra detail is about outputs/ids used downstream, not about this parameter, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('List') and resource ('available placements for a profile') and then disambiguates the abstract term 'placement' per platform, so an agent cannot confuse it with siblings like profiles_list or profile_groups_list. The per-platform enumeration removes all ambiguity about what a 'placement' is.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives strong downstream context (e.g. Google Business 'locations' come back as resource paths to pass as location_id; WhatsApp placement id is the phone_number_id consumed by whatsapp_* and dm_chat_create), which effectively tells the agent when the output is needed. However, there is no explicit exclusion or 'call this before/after X' instruction, so it stops short of full when-to-use routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.